1. Field of the Invention
The present invention relates to a running machine and more particularly to an indoor running machine mainly used for health, medical cure or training purposes.
2. Description of the Prior Art
One of the examples of the prior art running machines is shown in FIG. 9.
The illustrated running machine is provided with a running plate 4 provided between an upper portion 3a and a lower portion 3b of an endless belt 3 which is mounted on a lower support 1 and bent at a front end and a rear end, an upper surface of the upper portion 3a being a surface on which the user run or walks, the running plate supporting the upper portion 3a of the endless belt 3 and coming into a sliding-contact with the upper portion 3a. The running machine is also provided with a driving roller 5 for rotating the endless belt 3 mounted in an inner portion of the front end of the endless belt 3, a support roller 6 for rotating the endless belt 3 mounted in an inner portion of the rear end of the endless belt 3, and a driving unit 7 for rotating the driving roller 5.
The driving unit 7 transmits the rotation of a driving motor 8 to the driving roller 5 via a power transmission unit 9. The power transmission unit 9 includes a driving sprocket 9a mounted on a rotating shaft of the driving motor 8, a driven sprocket 9b mounted on a shaft of the driving roller 5, and a timing belt wound around both the driving and the driven sprocket wheels 9a and 9b. 
In use, the user mounts the upper surface 2 of the upper portion 3a of the endless belt 3 from a side of the front end thereof and sets the number of rotations per time unit of the driving motor 8 of the driving unit 7 by using a controller (not shown). Next, the user walks or runs on the upper surface 2 according to the speed of the endless belt 3 after having set the endless belt 3 in motion.
However, in the prior art running machine described above, when mounting the endless belt 3 or getting down from the running machine, the user, especially, the elderly or the disabled, experiences difficulty if the height H from the ground G to the upper surface 2 of the endless belt 3 is too great. Furthermore, when the user fails to keep pace and is driven to the rear end of the endless belt 3, a small height H would be desirable in order to reduce the shock if the user falls down.
In order to solve this problem, it has been proposed to reduce the distance L between the upper portion 3a and the lower portion 3b of the endless belt 3 by reducing the outside diameters of the driving roller 5 and the support roller 6.
However, in the prior art running machine, since the driving roller 5 transmits its rotation to the endless belt 3 by frictional resistance, if the diameter of the driving roller 5 is reduced, the frictional resistance between the endless belt 3 and the driving roller 5 is also reduced, thus increasing a possibility of slippage therebetween and therefore of transmission loss. For this reason, reducing the diameter of the driving roller 5 has many limitations.
It is, therefore, a primary object of the invention to provide a running machine having a reduced height from the ground to an upper surface of an endless belt without reducing the diameter of the driving roller.
In order to achieve the object, the present invention proposes a running machine comprising a lower support having side frames, an endless belt provided between said side frames, having an upper surface on which a user can run, a running plate having a sliding surface coming into sliding contact with a lower surface of an upper portion of the endless belt, a driving roller for rotating the endless belt mounted in an inner portion of a frontal end of the endless belt, a sliding member for guiding the rotational movement of the endless belt mounted in an inner portion of a rear end of the endless belt, a driving unit for rotating the driving roller. The running machine further comprises a tension member mounted near the driving roller and which depresses the upper portion of the endless belt toward a lower portion thereof to maintain a tensioned state of the endless belt so that the distance between the upper portion and the lower portion of the endless belt is smaller than the diameter of the driving roller.
According to the latter feature, the distance between the ground and the upper surface of the endless belt can be significantly reduced.
The user mounts the endless belt from a side of the rear end thereof. The small height of the endless belt facilitates the access to the user.
After having started the rotation of the endless belt, the user walks or runs on the upper surface of the endless belt according to the speed thereof. During his exercise, even if the user missteps or is driven to the rear end of the endless belt, the user will experience a smaller shock due to the small height between the ground and the upper surface of the endless belt.
When the user wants to stop exercising, he gets down at a side of the rear end of the endless belt. The reduced height compared with the prior art allows the user to easily get down from the running machine.
In a preferred form of the invention, the tension member is a roller adapted to be rotated in response to the rotational movement of the endless belt. In another embodiment, said tension member is a sliding element coming into sliding contact with the endless belt.
Advantageously, a tension adjusting unit is provided for adjusting the depressing force of the tension roller onto the endless belt so as to maintain a proper tension of the endless belt and a proper rotational movement of the endless belt.
The aforesaid sliding member for guiding purposes may be formed as a roller which rotates in response to the rotational movement of the endless belt.
Alternatively, the sliding member may be formed as a member coming into sliding contact with the endless belt. In this case, the sliding member may be integrally formed with the running plate as an end part thereof.
The driving roller may be arranged and positioned so that the lower tangent line of the driving roller lies within the plane defined by the lower portion of the endless belt along the running plate. For this reason, it is possible for the lower portion of the endless belt to be wound around the driving roller without bending the lower portion thereof. Accordingly, the endless belt has a simplified structure and a reduced resistance and can be properly rotated.
Alternatively, the driving roller may be arranged and positioned so that the lower tangent line of the driving roller lies above the plane defined by the lower portion of the endless belt along the running plate. An auxiliary contact roller member coming into a rolling contact with the upper surface of the lower portion of the endless belt may be mounted in a front end of the running plate near the driving roller. This configuration can increase the adaptability of the member into the various situations related to the installation of the driving roller, facilitating a wider use of the machine.
In this case, the auxiliary contact roller member may be formed as a roller rotating in response to the rotation of the endless belt.
The auxiliary contact roller member may also be formed as a member coming into a sliding contact with the endless belt.
The aforesaid lower support may be provided with a cover for protecting a lower surface of the lower portion of the endless belt. Accordingly, the endless belt is prevented from being worn by the contact with the ground, thus increasing its durability.
In addition, an inclined plate may be provided, which extends from the ground to the rear end of the endless belt. The user may easily mount the running machine and get down more safely. Particularly, during his exercise, even if the user missteps or is driven to the rear end of the endless belt, the user may step on the inclined plate, thus reducing the shock or deviating from the danger situation. The distance or height between the ground and the upper surface of the upper portion of the endless belt is equal to 40 mm or lower, in a preferred embodiment. This value allows the user to easily get onto or get down from the endless belt from a side of the rear end of the endless belt.